#include <bits/stdc++.h>
using namespace std;
struct Cross {
uint64_t inner, outer;
};
uint64_t SelectCross(int32_t K, vector<int32_t> I, vector<int32_t> O) {
const uint32_t N = I.size();
vector<Cross> crosses(N);
for (uint32_t i = 0; i < N; i++) {
crosses[i].inner = I[i];
crosses[i].outer = O[i];
}
sort(crosses.begin(), crosses.end(), [](Cross a, Cross b) {
return a.inner > b.inner;
});
// Comparator for priority queue that will force the smallest outer to the top
const auto cmp = [](Cross a, Cross b) {
return a.outer > b.outer;
};
// Priority queue that keeps the k Cross elements with the largest
// outer diameter out of the ones that we have processed so far.
// And allows popping the one with the smallest outer diameter.
priority_queue<Cross, vector<Cross>, decltype(cmp)> q(cmp);
// Keep track of the best area so far
uint64_t best_area = 0;
for(const auto &c : crosses) {
q.push(c);
if (q.size() < static_cast<uint32_t>(K)) {
continue;
} else if (q.size() > static_cast<uint32_t>(K)) {
q.pop();
}
const auto inner_size = c.inner;
const auto outer_size = q.top().outer;
best_area = max(best_area, 2 * inner_size * outer_size - inner_size * inner_size);
}
return best_area;
}
